[ultraflo]

As far as size, I would get the 2.5 inch H or X-pipe...

If you're not wanting to spend alot of dough that's fine with me, just keep in mind that if you plan to keep your stang for a long time, spend the extra money and buy a stainless pipe rather than the cheaper aluminized tubing, the Macs have some type of coating on them that holds up okay. I ran a powerchamber by mac that was nice, I now run a stainless bassani 3" Xpipe